818019021 has 4 divisors (see below), whose sum is σ = 1090692032. Its totient is φ = 545346012.

The previous prime is 818019017. The next prime is 818019043. The reversal of 818019021 is 120910818.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 818019021 - 2² = 818019017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 818019021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (818019061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 136336501 + ... + 136336506.

It is an arithmetic number, because the mean of its divisors is an integer number (272673008).

Almost surely, 2^818019021 is an apocalyptic number.

It is an amenable number.

818019021 is a deficient number, since it is larger than the sum of its proper divisors (272673011).

818019021 is a wasteful number, since it uses less digits than its factorization.

818019021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272673010.

The product of its (nonzero) digits is 1152, while the sum is 30.

The square root of 818019021 is about 28601.0318170516. The cubic root of 818019021 is about 935.2358241080.

Adding to 818019021 its reverse (120910818), we get a palindrome (938929839).

The spelling of 818019021 in words is "eight hundred eighteen million, nineteen thousand, twenty-one".